In some conventional systems, a transmitter may broadcast radio frequency (RF) signals. Generally, RF signals are generated by upconverting baseband signals to intermediate frequency (IF) signals, and then further upconverting the IF signals to RF signals, or directly upconverting from baseband signals to RF signals. The RF signals may be amplified by power amplifiers before being transmitted by a transmit antenna. Due to the proliferation wireless devices such as telephones, walkie-talkies, personal digital assistants (PDAs), and routers in home computer networks, a transmitted signal need to be at a certain minimum strength in order for a receiving device to demodulate the transmitted signal.
Generally, controlling output power of a transmitter is important to minimize interference with other transmitted signals while still providing enough transmitted signal strength to allow a signal to be properly received and processed by a receiver. In addition, a transmitter of limited power source, for example, that in a mobile communication handset with a small battery, may need to accurately control power output in order to maximize battery life. However, a problem is that performance of various electronic devices, for example, resistors or semiconductor devices on integrated circuits may be affected by temperature. As temperature rises, a resistor's resistance may increase, thereby affecting current and voltage, and vice versa as temperature decreases. Transconductance of MOS transistors may also change with temperature and hence affect a circuit's performance. Furthermore, an inductor's quality may also change with temperature and thereby affect an RF amplifier's gain when the inductor is a load. Similarly, the current that a transistor on a chip may conduct may vary as temperature changes. The change in current and/or voltage may change the transmitter output power.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.